Flour bleaching apparatus



May 22, 1956 F. M. ABBOTT ET AL 2,746,375

FLOUR BLECHING APPARATUS Filed Oct. 9, 1952 2 Sheets-Sheet 1 /NVEAN'URSFEDWC M. BQTT @EM/ER Q.. ELSLY May 22, 1956 F. M. ABBOTT ErAL FLoURBLEACHING APPARATUS 2 Sheets-Sheet 2 Filed Oct. 9, 1952 S Tm TTL NO V LWBA AB MG. ma RE DV EN RE FD w .x m v0. n w m 3 6 4% I .b

HENRY F. BAMESBERGER AT TORI/EY FLoUR BLEAcrnNG APPARATUS FredrcMrAbbott, Monterey Park, Denver Balsley,`

Los Angeles, and Henry F. Bamesberger, Anaheim, Calif., assignors toGeneralMills, Inc., a corporation of Delaware* Application October 9,y1952, Serial No. 313,886

12 Claims. (Cl. 99263) bleaching agent to remove the color and to turnit white.V

Through custom and habit, and perhaps the association of whiteV withpurity, the consumer, in many cases, demands that the flour be white,making it necessary t bleach the flour to satisfy competitiverequirements. In order to obtain a uniform and thorough bleach the ourmust be subjected to thorough contact with a bleaching agentl for acertain period of time. A frequently used method is to create anatmosphere of bleaching gas and pass the our in an agitated statethrough the gas. In some methods known to the art, the Hour is subjectedto mechanical agitation in the presence of `bleaching gas, whichnecessitates the provision of operating machinery and power. Attemptshave been made fto successfully subject ilou'r to the action of ableaching gas by dropping it through a zone containing bleaching gas. Asthe our Vis dropped, thorough contact between the flour and gas is hadby the flour striking objects which cause dispersion, such as inclinedsurfaces which cause the flour to cascade back and forth. These devicesoften are lvery large in size to accommodate a satisfactory flow ofilour without clogging and frequently do not bleach evenly as the our isnot evenly distributed through the gas as it passes through the`distribution apparatus. Further, variances in flour ow often result inthe clogging of the ilow.' The iiour frequently concentrates itself inone location, caus- UnitedStates Patent ICC Figurell is averticalelevation taken through the bleaching apparatus;

Fig. 2 is a sectional view taken along line 2-2 of Fig. 1;

and

Fig. 4 is anenlarged vertical section of a portion of the bleachingapparatus showing details of several features.

In the'present invention contact between the flour to be bleached andthe bleaching gas is obtained by dropping nely divided flour through azone which contains an atmosphere of gas. The zone is defined, as shownin Fig. 1, between the interior surface of the vwall of the enclosureshell 10 and the exterior surface of the our dispersing or deecting body12, which is suspended within the shell. The deflecting body is rigidand may be made of material such as molded plastic or non-corrosiveorcoated metal not subject to corrosion from contact withjbleaching gas. lf

The enclosing shell which forms a housing in which the our is bleached,is formed by an upper section 14 and a lower section 16 which are joinedtogether in a manner `to be later described. The assembled enclosureshell has a `central or .main body portion which is cylindrical inshape, shown in Figs. l, 2 and 3, and is positioned vertical in itsnormal operating position. The shell is preferably formed of a materialsuch as coated or non-corrosive ing clogging in one location and theresultant` clogging of the whole apparatus. i

Accordingly, an object of the present invention is to provide ableaching apparatus which will uniformly and evenly bleach` ilourwithout requiring the provision of mechanically driven agitators foreven distribution of the llour through a bleaching gas and which willhandle a relatively heavy flow of flour distributing it thoroughlythrough the gas. t

Another object of the invention is to provide a `gravity ow ilourbleacher which will not clog and which will automatically relieve itselfof small concentrations of our which would normally fill and clog thepassageways through the bleacher. j I

Another object of the invention isl toprovide a gravity ilow flourbleacher which will cause a complete and even distribution of flourthrough an atmosphere of bleaching gas to insure continuous adequate andeven bleaching.

A still further object of the invention is to provide a bleacher formedwith a hollow enclosing shell which isiu sections and means fordistributing a bleaching gas within the enclosing shell which also willserve as a sealing gasket to prevent the escape of bleaching gas frombetween the therfollowing specification and claims, illustrated by thedrawings, in which metal not ksubject to corrosion from contact withbleaching gas.

The our dispersing body 12, suspended Within the entions of theenclosure shell are tapering sections 20 which i are conical in shape.The upper end has an opening 22 at the top through which the our entersthe shell and the lower end has an opening 52 through which the ilourleaves the shell after being bleached. vExtending above the upperopening 22 is a cylindrical extension 24 which receives the dischargeend 26 of arotary valve 28. A

stiffener 29 surrounds the extension 24 for strength and for weldingthesections together.

` The rotary valve receives our 30 through a llour supply pipe 32 and,as its cylinder 34 rotates, flour is dropped down through the valvedischarge 26 into the enclosure shell. As is peculiar to the design ofthe rotary valve, the our is gatheredin the pockets or cut away portionsof the cylinder 34 so that these small amounts will cause a pulsating orintermittent discharge of flour into the bleacher shell. This pulsatingor intermittent feed of the bleacher is of importance in that they causea continuous motion of the central dispersing body in a manner whichwill later be explained in detail. Although a rotary valve is preferred,various other 'devices yielding a varying rate of feed may be used. Ascrew conveyor, for example, might be used or a device specificallydesigned to yield a varying or pulsating rate of feed.

The design of the central our dispersion member or torpedo 12 and itsposition and use relative to the remainder of the apparatus is basicallydirected at preventing concentrations of our from shaking the mechanism`and it also serves to obtain an even-dispersion of It is to be notedthat the bleaching zone 18, which is Fig. 3 is a sectional view takenalong line'S-S of Fig. 1;

. ,s Y anriulai i shape, 1s dened between two vertical walls,

other being the exterior surface of the dispersing member 12, At theupper end of the vertial wallzovfthe dis'pefs'ing ineibef, theveiticlwall surface. deviats to form an anglewith the vertical wall,vthe angular surface peak 38 at its tp. It is against this peak 3S thatthe our is dropped to bedivided and slid downthe inclined surface offthece 3f6i When the ilourkreachesthecentral 'yfliiidiicl p itiri 17, itflows oi the' `edge as a curtain voi? flour in a finely `divided stateto pass down the ljllliilg i 18;

The iiiif striking the peak 3sL is evenly divided s it llvvs` dwthecnicl surface` andthe horizontal comporin s the force o f thedropping llourare: also equal around the aids f the central member; Ii,however,I

any lagi-liiiiips filur' or concentrations fallto one side of the peak,there will" bea result at` horizontalcoiiipolnerit'of'foce which willtendto deilect `the surface It is these con-A awy' from theconcentration of flour. centrations which normally act to cause aclogging f'a gravity feed flour bleacher. The cloggingoccurs at oneVlocatift'n andgenerally builds up to result in the eventual t cloggingof the wli'ole machine.

lt is an irripcir'tantA feature of applicants mechanism that 'thecentral member, isfreelysuspende'd withinthe bleaching enclosui'e, thuspermitting free lateral Ideflection when a horizontal 'force/isexercised upon it, In other words, sincethe ccntralldeilecting member 12is not restrained in a horizontal direction, flour falling unevenly onthetapered upward surface willuonause sidewise movinentof thecentraldisper'sing body. The movement of th body will change the spacebetween the enclosure `shell `1D and the surface ofthe body to `tend torelease any concentrations of ourwhich rnight momentarily be depositedor caught in the space. The free suspension of the central mefnberpermits it to have horizontal Vmovement away fiomany concentrations offlourwhich form between: the wallsat any of thevlocations between'thesuspended rigid body and the shell.

conical surface: The upperends of the spring are hooked to eye-bolts 44which extend through a hollow boss mounted on th outer surface of theupper tapered end of the enclosing-shell. A pairof nuts {iS-are threadedto the-end of the bolt andradjustrnent of these nuts will serve tocenter the suspension ofv the dispersing' body; Iii addition tothe fr eelateral movement V-atiordedy by the suspension of the dispersing body,the springs permit a vertical movement of the body As the flour isdropped intermittently against the top of the dispersi-ngbody, it causesan expansion of the springs and a downward movement of the bcdy. Betweendrops of our the springs contract. Thus, with a continual feed of flour,a vertical oscillation is given to the 'central body. This oscillationcauses a relative Vmovement between the central body and enclosureshell, thus additionally .preventing the Vopportunity of a build up ofconcentra-tions'of ilour and resultant clogging'or choking. kFlourdropping` unevenly on the conical top orto one side uf the .peak willcause an extension ofthe supprtin'g springon that sidepre'siulting inhorizontal deflection of the 'central dispersing bod'y yielding eiitiaspace to 'permit `1ass`a"g`e of the vHour,

Therefore, it will be seen that the central 'torpedoshaped aisne/Isingbody is innnntea 'fn have@ continual vertical movement 'from theirregular admission f from and that the body is also free to havel'ateral'nivemeilt to release any concentration of our which mightoccur. ThisN iliill f ioVitS Will 'liit' arly clogging with a normalfeed of flour, and will cause an improved dispersion of the flourthrough the bleaching gas. f

At the lower end of the bleaching apparatus where the bleached our isdischarged and the enclosure shell 10 tapers inwardly theconiclly-'shaped surface 50 leads to a tubular extension 52, havingvatits lower end a rotary vali/e 5d. 'The rotary' valve isnthe same size'and is caused to rotate at substantially the same or slightly greaterspeed than the upper rotary valve sothatthe bleached our gathering atthe bottom will be removed. The rotaryL valve forms a seal at the lowereiidof the enclosure shell preventing the escape of bleaching gas intothe surrounding air. i

The lower end of the central torpedo-shaped dispersing body terminatesin a cone-shaped surface 56 which leads directly from the cent ralcylindrical portion 11i.y The surfaces of the conical tips 56 and 36 of`the central torpedo are parallelat both ends20 and 500i the shell sothat the central dispersing body is free to move sideways `withintheshell,

A nimportant feature of the invention is the apparatus for introducingbleachinggas inthe bleaching'zone, For convenience of assembly, theenclosure shell 10 is made into sections, the upper section 14 and thelower section 16. This permits the central dispersing body tobe made inone. section and the apparatus is assembled by iirst suspending thedispersing body fromits springs at the top and then placingthe lower endof the shell over the dispersing body.v For purposes of securingtogether the upper and lower sections ofthe shell, kannular rings 59 and61 are secured to the upper and lower sections and have outwardlyextending llanges 55 and 57. To these flanges are secured projections 63and 65 which are spaced from each other and have holes for bolts 60 towhich are threaded nuts 62 to hold the shell sections together. l

Advantage hasbe'en taken of theV separation of the enclosure shell toprovide a v4means for admission of a bleaehinggas. ,A continuous annulartube 64 is provided having a slightly larger annular diameter than theenclosure shell-so vthat it may be positioned between the flanges 5'5and-57 of .the annular rings S9 and 6.1secured to the upper and llowersections of the shell. The annular tube serves both as a manifold orheader fothe bleaching gas and as a gaskets'ealing the-shell from escapeof ga's, Thel tube `isma'cle of a resilient material, such as a hardrubber, which when the nuts 62 are drawn up on the` bolts.L 60 sealsitself securely against the brackets 49 to form va gasket.

In the outer 'face o'f the annular tube (Fig. 3) is an opening forksupplying bleaching gas. A lhollow .pipe 66 is provided on theopening-for attaching a gas supply hose.. AThe bleaching gas is thus fed'tothe hollow 68 within the annular tube and passes through a series ofinwardly directed openings 70 into the bleaching zone 18 of theenclosure shell. To direct the gas inwardly and downwardly small plasticnozzles 72 are inserted into the holes 70 and through their openings thegas is fed from the tubular manifold 64. These nozzles 72 are arra'ngediniany desired number around ythe bleaching zone and direct the gasdownwardly into the zone. The nozzle's are directed slightly downwardlyto insure distribution of the ygas the full length of the zone although,duringk operation, the gas distributes itself throughout the entire`spaceA between the -dispeising body and the enclosure shell.

- Thus-,iii the arrangement 4shown the lhollow annu1ar 'shapedftb'eIserves as a manifold `or header to distribute the bleaching gasentirely around the 'enclosure Ishell 'and 'also sife's Svv'a'S'eal-ir'ig gasket 'to v"prei/eilt the 'e'scpe of gas 'frenibetween the sections ofthe shell.

andere To give manual access to the interior of the bleacher and forpurposes of observation or checking whether gas is present within thebleacher, a group of handholes 71, 73 and 75 are positioned around thetop of the enclosure shell. The handholes which are identical and inwhich like numbers indicate like parts (Figs. 1 and 2) are formed by anannular flange 74 which extends out from the tapered surface 20 of theenclosure shell.` Against-the edge of'this flange is placed a' cover 76which has a bar 78 extending diametrically across its top to extendbeyond j the edge of the cover, for purposes of securing the cover v tothe hole.

, studs 88 which extend through slots in the ends` of the bars 78 toreceive thumbscrews S2 which removably hold On each side of the handholeare welded provision of a relatively small amount of space and whichlexcept for the-rotary valve requires no power to operate, yet theapparatus insures a complete and uniform mixture `between the bleachinggas and flour and yields an evenly bleached product. The freely andresiliently mounted dispersing body has free lateral movement com- Y lbined with vertical oscillation during operation which gives a completedispersion Vof flour. This combined movement prevents any cloggingofflour in the apparatus and enables handling of uniform' or iuctuatingfeeds.

We have, in the drawings and specification, presented a detaileddisclosure of the preferred embodiment of our invention, but it is to beunderstood that as the invention is susceptible of modifications,structural changes 'and various applications of use within the spiritand scope of preventing `the` escape of gas and through which flour' isintroduced to strike the inclined surface and pass down `through -thebleaching gas, means for` dropping the our onrthe inclined surface togive motion to the suspended body, and means at the bottom of thehousing for removing the bleached our at the rate at which it isintroduced gas.

4. An apparatus for bleaching flour comprising in combination a hollowshell having a vertical cylindrical interior, a substantiallycylindrically-shaped body coaxialf ly suspended within the shellproviding an annular bleaching passagewaybetween them, the-body beingfreely sus-- pended to be free for unrestrained lateral movement, meansfor introducing a bleaching gas between the shell and cylindrical body`to provide a bleaching atmosphere in vthe passageway through which theflour drops, means for dropping flour on the top surface of thecylindrical` body to give motion to the body with the flourpassingthrough the bleaching gas, and means for removing thebleached our at arate` as fast as it was dropped into the shell after ity has passedbetween the shell and cylindrical body. v

5. Ans-apparatus for bleaching flour comprising in combination a housingWithin which the our is bleached,` a deiiecting body freely suspendedwithin the housing to be capable of unrestrained lateral movement tofree concentrations of flour between the body and the housing, means todrop flour at an uneven rate into the top of said housing on thesuspended body, the flour being dropped at an unevenrate to cause aninstability of the suspended body which aids in dispersing the ilour,means to create an atmosphere of bleaching gas within the housing, andmeans to discharge the bleached iiour from the the invention, we do notintend to limit the invention to the specific form disclosed but intendto cover all modifications, changes and alternative constructions andmethods falling within the scope of the principles taught by ourinvention. v

We claim as our invention:

l. An apparatus for "bleaching our comprising in combination anenclosure shell in which our is subjected to an atmosphere of ableaching gas, means for injecting kbleaching gas into the shell, arigid body within the enclosure shell, means connected to the bodyfreely suspending the rigid body within the shell capable of freelateral movement, means `for introducing flour through an opening in thetop of the shell to permit it to drop down and strike the rigid body togive motion thereto and be dispersed between the shell and body to passthrough the bleaching gas and means at the bottom of the shell removingthe flour as rapidly as it enters the shell at said j top opening sothat it Will not pile up against said body.

2. An apparatus for bleaching flour comprising in combination anenclosing container in which intimate contact between a bleaching gasand the flour occurs, means for creating an atmosphere of bleaching gaswithin the container, a body having a conically-shaped top for evenlydispersing the iiour, a support for the conically-topped body, said bodybeing suspended from the support without lateral restraint Within thecontainer and for being capable of free lateral movement, means to feedour to the bleacher by depositing it on the conical top of said body togive motion to the body, and means for removing flour from the bottom ofthe container as rapidly as it is deposited on said body, so that itwill not pile up within the container.

3. An apparatus for bleaching flour comprising in combination a housing'within which lthe flour is subject to i Contact with a bleaching gas,means for introducing gas into the housing, a rigid body having aninclined upper surface for deecting the flour and being freely suspendedwithin the housing, means in the top of the housing housing as fast asit is dropped in the housing.

6. An apparatus for bleaching llour comprising in combination anenclosing shell in which the flour is subjected to a bleaching gas, abody freely suspended Within the shell being capable of free lateralmovement in response to a force having a horizontal component, means toinject a bleaching gas into Ithe interior of the enclosing shell, arotary valve. positioned at the upper end of the enclosing shell above`the freely suspended body to int troduce unbleached liour into theshell by intermittently dropping the ilour onto the freely suspendedbody to cause an unstable condition thereof to prevent concentrations ofllour from jamming between the body and the shell, and means todischarge bleached ilour from the lower portion of the shell after ithas passed through the gaseous atmosphere within the shell as fast as itis dropped into the shell.

7. An apparatus for bleaching ilour comprising in combination a hollowenclosure in which our is subjected to an atmosphere of bleaching gas,means for creating the atmosphere of bleaching gas within the shell, abody resiliently suspended within the enclosure so that flour strikingthe body will cause motion of the body, the space lbetween the bodyinterior of the enclosure forming a bleaching zone, means forintroducing flour into the top of the enclosure todrop down onto ltheresiliently suspended body and through the bleaching zone to contact thegas, and means for discharging the bleached our from the lower end ofthe bleaching zone as fast as it is introduced into the enclosure.

p 8. An apparatus for bleaching our comprising in combination a hollowenclosure in which flour is passed through an atmospheric bleaching gas,a body positioned within the interior and defining a bleaching zonebetween the body and the interior of the enclosure, means for in`troducing unbleached our into the top of the enclosure to drop down andstrike the body to pass through the bleaching zone, a spring meansresiliently ysuspendingV said body within the enclosure so that the bodyhas' free movement when it is struck by the our to preventconcentrations of flour from building up between the body atfthe top ofthe housing and preventing the escape of troduoed' into the top of theenclosure after it has. passed Y through the bleaching zone.

9.-Anfapparatu's for bleaching inout comprising in coinbination -anenclosure'lfor passing flour through -a bleache ing gas, means forintroducing thebleaching gas into the' enclosure, a kbody suspended'Within the enclosure to de-Y iin-e a bleaching'zone betwtfecnl itsexterior and the enclo sure, spring means for resiliently suspending thebody witiiin tholnolosure, vmeans for introducing hour into theenclosure' ata` rapidly varying rate so' that the force of the flourAdro'tnting on' the body will vary to cause the body to .have verticaloscillation to prevent the build up of concentrations. of flour", `andmeans for-'discharging' the bleached nour from the enclosure as fast asit is introduced vinto 'the enclosure, l

' l0.y AnY apparatus for bleaching nous comprising in combination-firstVand second mating enclosing shell menibers whichwhen assembled form ahousing within which flour-fis `to be'bleached, a bleaching gas supplyVmanifold formed of a hollow tubing of resilient material with means forreceiving ygas within itshollow and for discharging gas into theenclosing shell members, the resilient supply manifold positionedbetween the nist and second mating parts to' form a gasket Preventingthe escape of gas from the shell, means to hold the shell membersagainst the resilient manifold, .means vfor introducing` llour into theshell to contact the bleaching gas introduced `through the manifold, andmeans for discharging vthe bleached gas from the shell..

11. An apparatus for bleaching flour vcomprisilstg in combination shellmembers' forming a housing for bleach-v ing llour'and having annularmating edges which join to complete the enclosing shell, an annular ga'ssupply manifold formed of a hollow tube with a vplurality Yof 8 radial:inwardly Yfacing openings forv distributing "a bleaching gasto theinterior 'of the .shell andan outer opening throughA which gas islied/toA the manifold, the manifold beingclarnpcdv between. the annularedges of the shell members to act las a `,gasket and prevent escape ofgas, means for feedingA flour for bleaching to the housing, and mdansfordischarging the bleached our from the housmg, y

12.515311 apparatus for bleaching Ylonr comprising in combirthtionv anupper and .lower shell member .forming a housing for bleaching our andv.being cylindrical in shape, tapering 4respectively to al1 inlet and anoutlet opening', means orintnoducing flour through the inlet open ingVvto' pass Vthrough thesshellsto mingle with .a bleaching gas,l means for'discharging the bleached our through the outlet opening, an annularresilient hose forming a combination. bleaching gas, manifold andgasket, the hose having an. inlet for `introduction of a bleaching gasand a series of radial openings facing inwardly into which are insertedgas nozzles which project into the interior ofthe shell., and-means for:clamping the upper and lower shellmcmbcrs against theannnlar'manifoldto seal the shell interior against escapo of bleaching gas to lthe atrnosphere.

References -Cited inthe ile of this patent UNITED STATES PATENTS

1. AN APPARATUS FOR BLEACHING FLOUR COMPRISING IN COMBINATION ANENCLOSURE IN WHICH FLOUR IS SUBJECTED TO AN ATMOSPHERE OF A BLEACHINGGAS, MEANS FOR INJECTING BLEACHING GAS INTO THE SHELL, A RIGID BODYWITHIN THE ENCLOSURE SHELL, MEANS CONNECTED TO THE BODY FREELYSUSPENDING THE RIGID BODY WITHIN THE SHELL CAPABLE OF FREE LATERALMOVEMENT, MEANS FOR INTRODUCING FLOUR THROUGH AN OPENING IN THE TOP OFTHE SHELL TO PERMIT IT TO DROP DOWN AND STRIKE THE RIGID BODY TO GIVEMOTION THERETO AND BE DISPERSED BETWEEN THE SHELL AND BODY TO PASSTHROUGH TH BLEACHING GAS AND MEANS AT THE BOTTOM OF THE SHELL REMOVINGTHE FLOUR AS RAPIDLY AS IT ENTERS THE SHELL AT SAID TOP OPENING SO THATIT WILL NOT PILE UP AGAINST SAID BODY,